Guinea-Bissau's army has said it foiled a coup attempt in the impoverished
west African country and arrested the navy chief, accusing him of being the "mastermind"
of the attack.

Army chief of staff General Antonio Indjai said loyal troops had defeated the assault by renegade soldiers on army headquarters, which came while President Malam Bacai Sanha is undergoing medical treatment in France.

"A small group of soldiers" tried to "topple the top brass of the army and the government" but failed, General Indjai said. "The situation is under the control of the army and the government."

Navy chief of staff Jose Americo Bubo Na Tchuto was "considered the mastermind of this uprising," army spokesman Captain Samuel Fernandes said by telephone.

The attack on army headquarters and on two military units on the southern outskirts of the capital had been "contained", said Captain Fernandes, an adviser to General Indjai and a former army chief of staff.

He added that Rear Admiral Bubo Na Tchuto was detained and "other officers were also apprehended," naming a General Watna Na Lai.

A military source confirmed to AFP the arrest of Bubo Na Tchuto, and indicated he was being taken to Mansoa, about 60 kilometres (40 miles) north of the capital Bissau, where a military garrison is located.

Military sources told AFP that navy forces were among the attackers on Monday.

Bubo Na Tchuto - a controversial figure who has been repeatedly cited in investigations of drug trafficking - is a former ally of Indjai, but observers and local media say the two men have fallen out.

Since independence from Portugal in 1974,Guinea-Bissau's history has been studded with coups, army mutinies and political murders. It has also become a drug-trafficking hub, mostly for cocaine to Europe.

Military sources said the renegade troops overran the army compound at 6.30am GMT, firing shots in the air for close to half an hour.

There were no immediate reports of any bloodshed.

Fully armed men then fanned out across the capital, erecting roadblocks around the headquarters of the army general staff and in the avenue leading to the home of Prime Minister Carlos Gomes Junior.

Troops from different units could be seen, armed with machine-guns, Kalashnikov assault rifles and rocket-launchers.

Gomes briefly took refuge at the Angolan embassy, after soldiers paid him a short visit at his house, located opposite the embassy, according to two close aides and a non-Angolan diplomat.

General Indjai told reporters about the morning's events: "We were caught off guard this morning by armed men who attacked the joint command as well as two other military units inside the headquarters.

"These men were attempting to get hold of weapons we had stored in the gun shop," he said.

The military action took place in the absence of President Sanha, who is currently seeking medical care in France.

The presidency earlier this month denied rumours that the 64 year-old, who has spent most of his term in and out of the troubled country for health reasons, had died in a Paris hospital.

The president, who was elected in 2009 after his predecessor was assassinated, was admitted to a hospital in neighbouring Senegal last month before being transferred to the French Val de Grace hospital.

Earlier Monday, sources among the mutinous soldiers dismissed any suggestion that a coup was being staged in the absence of the president.

A soldier presenting himself as one of the leaders of the deployed forces said the troops were out to demand a pay rise, claiming: "This is a purely military problem. We have no intention of attacking the state."

Bubo Na Tchuto has long been a highly controversial figure.

In August 2008, the late General Batista Tagme Na Waie, then chief of staff of the armed forces, accused him of trying to stage a coup against then president Joao Bernardo Vieira.

Tagme Na Waie was killed in a bomb attack and Vieira was assassinated by soldiers in 2009.

In May 2010, a military court closed the attempted coup case against Bubo Na Tchuto, who was soon after named navy chief of staff.